<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        * {
            padding: 0;
            margin: 0;
        }
        .box {
            width: 500px;
            height: 800px;
            border: 1px solid red;
            display: flex;
            justify-content: space-around;
        }
        .box > div{
            width: 200px;
            height: 200px;
        }
        .first {
            /* 当父元素的宽度 不够一行子元素宽度之和 flex-shrink 来决定谁承担最多  默认为1*/
            flex-shrink: 0;
            background-color: red;  
        }
        .second {
            background-color: yellow;
        }
        .third {
            background-color: black;
        }
    </style>
</head>
<body>
        <div class="box">
                <div class="first"></div>
                <div class="second"></div>
                <div class="third"></div>
    
</body>
</html>